What sets Volt and CAS rate for RAM in a BIOS w/o these settings ?

I am looking to upgrade my RAM on a old HP ze4560us laptop.

The BIOS is a very simple one and has absolutely no adjustments for anything really including and CAS or Voltage adjustments for the RAM

The Stock RAM that is in the unit now is 2 sticks of 256 mb 200 Pin PC2100 SODIMM's that Everest Home reports as running at 2.5-3-3-6 @ 133 MHz and 2.0-2-2-5 @ 100 MHz (what ever that means by giving me two readings)

At any rate as HP's upgrade and some other forms of info have recommneded to me I think I can go with a PC2700 Ram or maybe even a PC3200.

At this point I don't know if I the FSB will run any higher then 133 so I know it may not be worth the extra cost but in this cast it really isn't all that much but the only thing I wonder how the BIOS is going to see it and what it may set the CAS rating at, especially if I go with the PC3200.

So how do most BIOS's like this set the CAS and voltage, is it done via some type of sensing of the RAM, will it set the voltage higher via som way like that too?

Anyway thanks for any advice.

 

The FSB of the processor is going to be the maximum speed of the RAM that you can get.

So if you look up the processor specifications, you can find out what you can install no problem.

 

Most likely the BIOS doesn't show any configuration options for those items because _HP chose not to make such options available (or even visible); however, the underlying functionality is still there in the BIOS. The setting for the RAM in your system would be checked on POST when the BIOS goes through its start-up procedures.

 

Hey Greg and thanks for the reply, the processor in this LT is a AMD Mobile Athlon XP-M 2500+ PN: AXMH2500FQQ4C

It ratings at this page: http://www.cpu-world.com/CPUs/K7/AMD-Mobile Athlon XP-M 2500+ - AXMH2500FQQ4C.html

.. states that it rated at 266, which I guess really means 133MHz, so in this case is the bus being "set" by the processor in some way or is it the other way around.

I guess I'm having more trouble understanding this as for a long time I have been using Asus mother boards that allowed me to adjust stuff like this and was much easer to do research on, so now that it is going to be setting its own parameters I don't know what is going to be the override thing that controls it.

 

Yeah I figured it has to getting set by the BIOS and just hidden which sucks, it would have been nice to at least see what it is setting it to even if I couldn't adjust it but there is virtually nothing that is visible in the BIOS, which being uses to the ones in my Asus boards is pretty ruff.

I should mention that I even got a editor and checked over a copy I made of it to see if I could find any further mentions of any parameters there but I couldn't find anything that way either, guess is just buried deep in the code and I'll just have to hope it has the ability to recognize everything correctly for what I get.

Basically the thing that I would like to know is if I go with the PC2700 or 3200, will the BIOS make all the correct settings?

 

It usualy sets the ram to a standard-value when it comes to speed, some bios can lower the cas-latency by default if you put in higher-speed ram, as the higher speed ram can be operated with lower latency without a problem. Though it's always gonna be the standard-voltage for the ram if the BIOS doesn't have an option for increasing it.

The bios will make the correct settings yes. You can put in any kind of ram aslong as it's 200pin DDR. Even higher spec, though it's gonna run it at standard-spec. Most ram-modules has some SPD-profiles that's higher than standard, but that doesn't mean it's gonna run on the higher speed profile just because it has it, specially not in notebooks.


As an example, i have a notebook that runs the memory at 266Mhz.
If you look at my picture you see a higher specced ram, good enough for 333Mhz.
If you put these memory in a laptop that only takes 266Mhz, it's gonna use the 266mhz-profile along it's latency settings. So one thing you could win performance doing is that you get lower latencys.
As the new memory here will run at 266Mhz 4-4-4-12 instead of 266Mhz 5-5-5-15.
This is only true if you check the voltage set to a standardvalue, you can see all the values is specified with the standard-voltage at the bottom of that picture. So if the value is something else than a standard-value it's not gonna use any of the values that's non-standard.

Don't know if you get what i'm saying, but i'm saying you can win some performance by buying higher spec ram aslong as it has lower latency at the speed your memory wants to run on your laptop with a standard-voltage.


Even if i'm new at this forum doesn't mean i'm a newbie with hardware, not at all

 

Hey Mike and thanks for the reply, I pretty much understand what you mean, its just that for me, I always understood that if you go up in the bus speed for the memory you typically need to increase the volts to get it to run at that so I guess the confusion for me is as a result of a few things, one if you look up at HP's site for a memory upgrade in their accessories page these are the specs I get:

Part No: DX762A
Module Size: 512MB
Memory Type: DDR PC2700 • CL=2.5 • Unbuffered • NON-ECC • DDR333 • 2.5V • 64Meg x 64Meg

Next if I run Crucial's I get this:

Part No: CT526737
Module Size: 512MB
Memory type: DDR PC2700 • CL=2.5 • Unbuffered • NON-ECC • DDR333 • 2.5V • 64Meg x 64Meg

But at the Corsairs site I get this:

Part No: VS512SDS266
Module Size: 512MB
Memory Type: DDR PC2100 • CL= 2.5, the rest is not listed but I'm assuming it is the same as the ones above but it does list the rest of the latencies as 3-3-6 which are the same as my present RAM

But they also have these

Part No: VS512SDS333
Module Size: 512MB
Memory Type: DDR PC2700 • CL= 2.5, with the rest of the latencies as 3-3-7

and

Part No: VS512SDS400
Module Size: 512MB
Memory Type: DDR PC3200 • CL= 3, with the rest of the latencies as 3-3-8


Personally I would much rather go with the Corsair as I've used them in the past and have had good luck with them.

Now if I go with the PC2100 I now that will work without issues but with the others being not that much more expensive at all, if I go with the PC2700 or the PC3200 will my BIOS bring those down to the present PC2100 CAS settings I have, ie the PC2700 will go from 2.5-3-3-7 to 2.5-3-3-6 and the PC3200 will go from 3-3-3-8 to 2.5-3-3-6

My biggest fear is that the BIOS will run the PC2700 and PC3200 at PC2100 but then keep the CAS the same

In other words it would actually be worse to get a better PC rated module as the bus will set the PC rating and the RAM will set the CAS rating.

Then lets say it does reduce the CAS numbers, will they be able run at those lower rating with only 2.5 volts?

 

You only need to increase the volts on the memory if you're using anything above the standard for DDR-memory. Otherwise it's just using one of the preconfigured profiles wich all uses the standardvoltage.

If for example you get 400Mhz with cas5-5-5-15 memory that can run at that setting on standardvoltage, and you only need 266Mhz memory, you'll get much lower timings at standardvoltage as the memory will downclock itself and use lower timings to compensate the slower clock, it will be able to use very aggressive timings as it's specced at 400Mhz with standardvoltage, that usualy means it can do for example 266mhz 2-2-2-15 at standardvoltage.
It will only select a profile suited for standardvoltage and nothing else, as the motherboard will detect that so it can boot up properly.

I hope you get what i'm saying, cause that's the idea with all types of memory! Only nvidia-based motherboards will use a higher voltage(if you set the bios to read EPP) as standard for the ram if the memory has an EPP(enhanced performance profile) that goes along with the higher spec settings, though memorys always has a JEDEC-profile that's set after the standardvoltage. There are always several profiles so it'll work on basically all motherboards that supports that kind of memory-type (DDR, DDR2 and DDR3 aso)


Anyhow, if you buy the PC3200 it'll run at PC2100-speed but have lower timings than standard, i THINK. I cannot say for sure. But in most cases it's always like that as the higher specced memory can handle more aggressive timings at standardvoltage. And the timings are seleced with the help of the profiles. So check what the PC3200 has for timings at the PC2100-profile.


Hope i cleared your thoughts out.


Sorry for my lack of english, but i'm a swede hehe.


EDIT: Worth to know maybe is that i wrote a FAQ on swedens biggest OC-forum all about how memory will run on all kinds of desktop-motherboards, so i'm definately not new at knowing these things. Member since -01 with large amount of posts over there. ( here's the FAQ on that forum anyways, explaining what i just did here http://www.sweclockers.com/forum/showthread.php?s=&threadid=773012 + alot more, though it's no use for you guys, as you probably can't read swedish.. )
AFAIK notebooks has the same thing. So that's why i'm not 100% sure in my answer. But i'm 95% sure that it'll run much smoother with the higher specced ram as it will use lower timings set for the standardvoltage.

 

Hey Michel.K and thanks for the reply

Yeah I pretty much understand what your saying.

I guess the thing that caused me concern was, being that this was not an adjustable BIOS, that those parameters would go to some default that I couldn't control.

In other words I'm sure PC3200 in place of a PC2100 would be usable under some parameter that I could set it to but it might not at whatever parameter it goes to as the default, so I was just wondering what sets those parameters, the BIOS or the RAM?

I'm not sure if you may have saw this in one of my other threads but I ended up finding what I felt was a great deal of info from an online vendor of all places here in the States called Egghead. They are a great vendor and I use them all the time.

One of the great things about them is that they offer a customer review page for everything that is purchased and so I was able to go over those for the PC2700 and PC3200 RAM I was looking at and found that in cases where they were used in PC2100 systems, for the PC2700 it was about a 50/50% go/no go and for the PC3200 it was about a 20/80% go/no go. I gather it has a lot to do with what kind of laptop you have and its BIOS as well as other stuff.

After that I then I also spent some time on a online chat with one of what I assume was a Crucial's tech reps and told him my concerns and while we were going over things I found a PC3200 RAM that they make that I received as a compatible memory from their "scan my system" configurator that had a part number: CT713043 and he stated that it should work so I made sure to get confirmation from him that if they didn't work they would take them back and then ordered two sticks of that and they should be here today.

After a lot of research I kinda came to the conclusion that the only real way I'm gonna know for sure what will work is to just give it a try so I'll try these first and if there are issues I'll try the PC2700 that Crucial has part numbered for this lap which is PN: CT526737, then if that doesn't work I'll go with the Corsair PC2100.

But I just want to thank you an all the others that have helped me with the info from their posts, at the very least I have learned a great deal.

Thanks again

 

OK all just to give an update, I installed the two Crucial PC3200 PN: CT713043 modules that their scan system said would work on my ze4560us laptop an that a on-line chat with one of there techs said would work but they did not.

The Laptop tries but will not even boot and dies and just runs through a recycling of that.

I guess I will now have to return these and get the PC2700 ones they say will work and try those.

…way to go Crucial !!!

 

Just thought I would drop everyone a note and let them know that after returning the PC3200 RAM I got from Crucial I got their PC2700 that was more specifically part numbered for the ze4560us and it seems to be working great.

The Crucial PN for this RAM is CT526737 but the actual number on the RAM is CT6464X335.K8TKY

Which BTW as far as I can tell is a different end number then the one on their generic PC2700 200 SODIMM module.

I am using the latest BIOS the KA.M1.60

At this point CPU-Z is showing it is running at a 2-3-3-6 Latency on the 133MHz bus, which my old PC2100 ran at 2.5-3-3-6

I ran memtest for 8 hours which in that time it got to 1004.2% coverage and I had no issues and I have also run a complete file and folder backup of my root C: drive via a networked connection to a spare PC and everything went well and it even cut down the backup time from 2hrs 35 minutes to 1hr 32 minutes. So I guess you could say that the added amount of RAM and perhaps the tiny bit of lower latency defiantly made an improvement in the performance.

Also I should note that Crucial didn’t give me any issues on returning the RAM and credited back my CC account very quickly.

Hope this helps others.